There has been remarkably little research on the mechanisms that detect and signal conflict in cognitive processes, and even less on the role of conflict in the allocation of cognitive control. These questions are central both to our understanding of cognitive control. These questions are central both to our understanding of cognitive function, and to its disturbance in neuropsychiatric disease. The objective of this Center will be to identify and characterize the neural mechanisms involved in conflict and the allocation of control. Several convergent approaches, including computational modeling and formal mathematical analysis, cognitive behavioral testing, functional neuroimaging in adult humans and children, and direct neuronal recordings in non-human species will be used to test the following four Center hypotheses: 1) conflict in processing leads to adjustments in cognitive control; 2) the anterior cingulate cortex is selective responsive to conflict; 3) conflict detection and control are subserved by distinct neural systems; and 4) the influence of conflict on control is modulated by reward. The Center is organized into 7 projects and 3 cores led by highly accomplished scientists in the areas of attention (Casey, Posner, Treisman), memory (Cohen, Johnson) decision making (Kahneman, Shaffir), formal modeling (Holmes, Hopfield), and neurophysiology (Aston-Johnson) decision making (Kahneman, Shaffir), formal modeling (Holmes, Hopfield) and neurophysiology (Aston-Jones, Shizgal) from four institutions (Concordia, Cornell University of Pennsylvania and Princeton). Projects 1-4 will use human behavioral testing and neuroimaging (fMRI). Project 5 and 6 will use behavioral tasks paralleling human studies coupled with neurophysiology and neuroanatomy in monkeys and rats. Project 7 will use computational modeling and dynamical systems techniques to analyze neural network models of the tasks employed in the other projects. Three cores will serve the administrative and technical needs of the Center. These will include an Administrative Core to coordinate Center activities and oversee fiscal and reporting functions, a Neuroimaging Core to coordinate resources for conducting neuroimaging studies of human subjects, and a Computational Core to maintain hardware and software platforms necessary to analyze and visualize large-scale neuroimaging datasets and to conduct computational modeling. In addition to its research mission, the Center will also foster training of researchers at all levels, from undergraduates to participating faculty who are expanding their scientific approaches of cross-project collaborations.